Mass transportation system

ABSTRACT

A high speed mass transportation system, in which a train unit rides in an arcuately concave, narrow guideway and is aerodynamically supported on airfoils conforming to the arcuate form of the guideway. The center mass of the vehicle is below the center of radius of the guideway, which provides a selfstabilizing and automatic banking action in high speed turns, so that passengers are not subjected to lateral accelerations. The airfoils are spaced several inches above the guideway at cruising speed, so that the surface finish of the guideway is not unduly critical and cost is minimized. Retractable wheels are provided for supporting the train unit at low speeds and on flat surfaces. Propulsion may be by means of direct thrust, such as a propeller, or by electrical drive means, such as a linear induction motor.

United States Patent Girard et al.

[ 51 July 11, 1972 [54] MASS TRANSPORTATION SYSTEM [72] Inventors: PeterF. Glrard, La Mesa; John M. Peterson, San Diego, both of Calif.

3,477,387 ll/l969 Bing 104/23 FS 3,155,050 ll/l964 Hafner l04/l38 R3,52l,$66 7/l970 Van Veldhuizen... l04/23 FS 3,583,323 6/1971 Paris104/23 FS Primary Examiner-Arthur L. La Point Assistant ExaminerD. W.Keen Attorney-Carl R. Brown, Stephen L. King and Kenneth W. MateerABSTRACT A high speed mass transportation system. in which a train unitrides in an arcuately concave, narrow guideway and is aerodynamicallysupported on airfoils conforming to the arcuate fonn of the guideway.The center mass of the vehicle is below the center of radius of theguideway, which provides a self-stabilizing and automatic banking actionin high speed turns, so that passengers are not subjected to lateralaccelerations. The airfoils are spaced several inches above the guidewayat cruising speed, so that the surface finish of the guideway is notunduly critical and cost is minimized. Retractable wheels are providedfor supporting the train unit at low speeds and on flat surfaces.Propulsion may be by means of direct thrust, such as a propeller, or byelectrical drive means, such as a linear induction motor.

[4 China, 22 Drawing Figures FATENTEDJUL 1 i 1912 SHEET 10F T INVENTORSPETER F. GIRARD JOHN M. PETERSON u/mm ATTORNEY PATENTEDJUL 1 1 1912SHEET 2 OF 7 INVENTORS PETER F. GlRARD JOHN M. PETERSON ATTORNEY ENTORSETER F. IRARD OHN M. PETERSON lu 64m ATTORNEY SHEET 3 OF 7 NN U U D DPATENTEUJUL 1 1 m2 PATENTEDJUL 1 1 m2 3. 6 7 5 5 8 2 saw u or 7 Flg 9 6O ii;

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INVENTORS PETER F. GIRARD JOHN M. PETERSON az-aam ATTOR NEY PATENTEDJuL1 1 m2 SHEET 7 BF 7 INVENTORS PETER F. GIRARD JOHN M. PETERSON ATTORNEYMASS TRANSPORTATION SYSTEM BACKGROUND OF THE INVENTION In the field ofmass transportation, many different proposals have been made forincreasing vehicle speed. Studies have determined that a cruise speed ofabout 300 mph is practical for various stage lengths, with reasonableacceleration and deceleration. At such speed, wheels become impracticaldue to the loads and wear imposed by very high rotational speed. Anumber of tracked air cushion vehicles have been proposed or developed,in which a vehicle is supported on a special track by pressurized air,to provide a low friction bearing. Since air leakage must be minimizedto maintain the air cushion, clearances between the track and thevehicle are small and the track must be precisely made, at high cost.This is particularly true with high pressure air pad support, in whichclearance is a few thousandths of an inch. In addition to direct supportof the vehicle, cushioning or other support must be provided forhandling side loads and for stabilization in turns. In any sucharrangement, the air cushion requires a power source of considerablesize, which must be carried on the vehicle.

SUMMARY OF THE INVENTION In the system described herein, the generatedair cushion and its attendant power source are eliminated, resulting ina lighter and less complex vehicle. The guideway is a trough-like trackof arcuately concave cross section, and is readily constructed fromconcrete with simple forms. The train unit, or vehicle, comprises anelongated body supported on longitudinally spaced airfoils, which extendtransversely and conform to the arcuate shape of the guideway. At highspeed, the airfoils ride, in ground efl'ect, several inches above theguideway surface and provide lifting support for the vehicle. The centerof mass of the vehicle is well below the center of radius of theguideway cross section, which gives the vehicle an automatic rolling andself-stabilizing capability in banked turns, thus avoiding subjectingthe passengers to lateral accelerations The ail-foils are supportedbelow the vehicle body on legs which provide roll stabilization, andalso contain retractable wheels which are lowered to support the vehicleat low speeds and when stopped. Certain of the wheels are steerable formaneuvering the vehicle on a flat surface. By spacing the airfoils belowthe body, the transverse span of the airfoils can be reduced, minimizingthe required width of guideway. Some or all of the alrfoils are providedwith automatic flaps which vary the lift in accordance with pressurefluctuations and thus aid in damping longitudinal oscillations.Propulsion may be by propeller means at the rear of the vehicle, or byelectrical means such as a linear induction motor.

The primary object of this invention, therefore, is to provide a new andimproved mass transportation system.

Another object of this invention is to provide a new and imroved systemin which a vehicle rides in a concave guideway and is aerodynamicallysupported on airfoils conforming to the guideway in such a manner, thatthe vehicle is self-stabilizing in turns.

Another object of this invention is to provide a new and improved systemin which the vehicle has retractable wheels for support at low speeds,and for handling and maneuvering out of the guideway.

A further object of this invention is to provide a new and improvedvehicle which is adaptable to different means for high speed propulsion.

Other objects and many advantages of this invention will become moreapparent upon a reading of the following detailed description and anexamination of the drawings, wherein like reference numerals designatelike parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of apropeller driven vehicle in a section ofguideway.

FIG. 2 is a perspective view of linear induction motor powered vehiclesin a covered dual guideway.

FIG. 3 is a top plan view of the propeller driven vehicle.

FIG. 4 is a side elevation view thereof, with the guideway shown insection.

FIG. 5 is a side elevation view of the linear induction motor poweredvehicle.

FIG. 6 is a front elevation view, as taken from the right hand end ofFIG. 5.

FIG. 7 is an enlarged sectional view taken on line 7-7 of FIG. 5.

FIG. 8 is an enlarged front elevation view showing the cruising positionof the vehicle relative to the guideway.

FIG. 9 is a front elevation view showing the wheels extended.

FIG. 10 is a diagrammatic showing of the roll stabilizing action.

FIG. 11 is a diagrammatic showing of displacement as caused by excessspeed in a turn.

FIG. 12 is a diagrammatic showing of the stable turning position of thevehicle.

FIG. 13 is an enlarged sectional view taken on line 13-13 of FIG. 6,showing automatic flap structure.

FIG. 14 is a similar sectional view showing the flap lowered.

FIG. 15 is a diagram of the roll control rudders.

FIG. 16 is a side elevation view of a modified vehicle using only twoairfoils.

FIG. 17 is a top plan view of the arrangement of FIG. 16.

FIG. 18 is a front elevation view as taken from the right hand end ofFIG. 16.

FIG. 19 is a diagram of the banking action of the modified form of thevehicle.

FIG. 20 is a transverse sectional view of a dual guideway.

FIG. 21 is a front elevation view of a leg with shock absorbing means.

FIG. 22 is a sectional view taken on line 22-22 of FIG. 21.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Three forms of the train unitor vehicle are shown, a propeller driven type III, shown in FIGS. 1, 3and 4 and a linear induction motor driven type 100, shown in FIGS. 2, 5and 6, both having multiple airfoils spaced along the vehicle. Of thesetwo, the propeller driven type will be described in detail, the onlydifference being in the means of propulsion and all other Figures of thedrawings being applicable to both types. The third type 140, shown inFIGS. 16-19, uses only two airfoils at the front and rear and can beoperated in a very narrow guideway where space is limited.

The vehicle I0 rides in a guideway 12 with a concave channel or trough14 of arcuate cross section, and having flangelike bafiles 16 extendingfrom opposite sides. At high speed the air flow disturbance caused bythe vehicle is considerable and the bafiles prevent debris from beingsucked into the guideway. The guideway is best made by conventionaltechniques with suitably reinforced concrete poured in simple fonns. Asmooth finish layer may be added on the arcuate face, as at 18 in FIG.8, but may not be essential. In a complete system the guideway wouldextend unbroken between selected destinations and, at certain terminals,would open to flat areas for vehicle servicing and related operations.In undulating terrain the guideway could be supported on pillars orother structure where necessary.

Since the vehicle operates in the performance range of a transportaircraft, construction may follow accepted aircraft practises,particularly for minimizing weight, no specific structural details beingshown. The vehicle 10 comprises an elongated generally cylindrical body20, with a suitably streamlined nose 22 and tail section 24. In the tailsection is a propulsion unit, shown as a gas turbine engine 26 drivingcounterrotating pusher propellers 28 through a gearbox 30. An air intake32 on top of the body supplies air to the engine and the exhaust outlet34 is directly downwardly. Flow directing means of well known type couldbe used to direct the exhaust rearwardly to augment the propellerthrust. In the nose section is a control cabin 36, the main cabin 38having suitable seats 40 and the body being provided with windows 42 anddoors 44, as necessary.

Spaced beneath the body are longitudinally spaced airfoils 46, eachsecured to the body by a pair of downwardly divergent legs 48. Eachairfoil is a small wing with suitably eambered surfaces for efficientaerodynamic lift and having pronounced arcuate dihedral conforming tothe cross section of the guideway trough 14. Each airfoil is mounted ata predetermined angle of incidence for effective lift, depending on theairfoil section used, and the required performance range. Six airfoilsare shown, but any suitable number may be used, the rearmost airfoilhaving extended legs 50 to suit the tapered tail section 24. By spacingthe airfoils below the body, rather than making them side extensionsfrom the body, the transverse span can be reduced since the area beneaththe body is clear of aerodynamic interference and can be effectivelyused. This allows the width of the guideway to be minimized, resultingin low structural and right of way costs. Each airfoil has downwardlyprojecting tip plates 52, which have an aerodynamic purpose incontrolling spanwise flow, and also serve as skids to protect theairfoil from contact with the guideway. Each leg is of streamlined crosssection and has a rearwardly extended lower portion 54, on which is ahinged rudder 56 controlled by a suitable actuator 58, as in FIG. 7.

In each leg is a wheel 60 mounted on a bracket 62, which is on the outerend of an arm 64, pivotally attached to the airfoil structure inboard ofthe leg. As shown in FIG. 9, the wheels extend, swinging about theinboard hinges 66 of arms 64, extension and retraction being controlledby telescopic actuators 68 connected between the upper portion of eachbracket 62 and fixed structure in the respective leg. In the extendedposition the wheels support the vehicle with the airfoils clear of aflat surface 70. To facilitate maneuvering the vehicle at terminalareas, the front and rear wheels are mounted on steerable brackets 72,as in FIG. 7, and are turned by actuators 74 coupled to any conventionalsteering system adaptable to the vehicle. The other wheels arepreferably similarly mounted for steering and are free castering withina limited range to avoid tire scrubbing. For convenience of handling,some or all of the wheels may be provided with individual hub mounteddrive motors, indicated at 76 in FIG. 9. Electrical and fluid poweredhub drive motors for such a purpose are well known. In the retractedposition the wheels project slightly below the airfoils, preferablybeyond the tip plates 52 to avoid any contact of the airfoil structurewith the guideway in normal operation.

The lift of a wing operating in ground effect is essentially inverselyproportional to the distance of the wing above the surface. Thus if awing sinks toward the surface, the under surface pressure and theeffective lift increase, tending to lift the wing to its normal stableposition for the particular speed. This has a natural damping effect onvertical oscillation and results in a smooth ride. Damping may beaugmented by means of automatic flaps, such as shown in FIGS. 13 and 14.Some or all of the airfoils can be fitted with flaps on portions oftheir trailing edges. In the under side of the flapped airfoil is acavity 78, in which is a vertically movable diaphragm 80, biased to aneutral position by a spring 82. A flap 84 is attached to the trailingedge portion 86 of the airfoil by a hinge 88, to swing downwardlythrough a small range. The flap 84 is connected to diaphragm 80 througha connecting rod 90 and bellcrank 92 so that, when the diaphragm isforced upwardly by an increase in pressure below the airfoil, the flapis correspondingly pulled down, as in FIG. 14. The lowered flap causes aconsiderable increase in lift for a slight variation in the height H ofthe airfoil above guideway surface 14, providing a very efi'ectivedamping action.

The rudders 56 are primarily for roll control, but can also be used foraerodynamic braking if required. A simple diagram of a typical controlsystem is shown in FIG. 15, in which a roll sensor 94, such as agyroscope, is coupled through a control valve 96 to actuators 58, tomove both rudders in the same direction in response to a roll deviationof the vehicle. The arrangement is comparable to a simple one axisautopilot and various systems are well known. For braking efiect, acontrol unit 98 is coupled to actuators 58 to move the rudders inopposite directions.

The vehicle 100 is similar in all respects except for the propulsionmeans. The linear induction motor 102, the principles of which are wellknown, comprises an armature 104 riding along a stator rail 106. InFIGS. 5 and 6, the armature is shown as a streamlined saddle elementstraddling the rail 106, which is above the vehicle and supported byspaced stanchions 108. To allow for deviations in height and rolling orbanking actions of the vehicle, the armature 104 is attached to a finstructure on the vehicle by an arm 112. The arm 112 has double universaljoints 114 and a roll axis bearing 116 at the forward end to accommodatethe various motions. Since the armature and stator rail can be made toclose tolerances by conventional techniques, the armature may besupported by a pressurized air cushion, not shown, to reduce friction.Power may be obtained from a power source in the vehicle. or fromconductors along the rail.

A development of the system is shown in FIG. 2, in which dual guideways14 are used to carry vehicles in opposite directions and are covered bya roof 1 18. The arrangement is adaptable to the vehicles 100 shown, orto the propeller driven type. Roof 118 is supported by truss members120, which include portions to hold the stator rails 106.

The width of the guideway 14 is not excessive but, where space iscritical, the configuration shown in FIGS. 16-19 may be used. In thisform the vehicle is lowered as much as possible and the airfoil spanreduced to minimize the necessary guideway cross section. The vehiclehas a streamlined body 142 with an underside 144 which is arcuate incross section to conform to the guideway trough 146.'Under the extremeforward portion of the body is a forward airfoil 148 supported on shortlegs 150 and at the rear is an aft airfoil 152 supported on legs 154.Both airfoils have arcuate dihedral conforming to the trough 146 and areprovided with end plates 156. The airfoils are mounted at suitableangles of incidence and positioned so that the body 142 also assumes asmall angle of positive incidence in cruising position, as shown in FIG.16. The body is as low as possible in the guideway and rides in groundeffect, so contributing to the aerodynamic lift.

Propulsion is by means of a linear induction motor 158 connected to thebody by an articulated arm 160 and riding on a stator rail 162. The legs150 and I54 may be provided with rudders and the airfoils may haveflaps, as described for vehicle l0. Retractable wheels may be mounted inthe airfoils and legs, or could be in the body in this configuration.

By lowering the body as much as possible, the radius R of the trough canbe minimized, while still keeping the vehicle center of mass 164 wellbelow the center of radius 166. The automatic banking and stabilizingaction, indicated in FIG. 19, is thus as described above, the desirableperformance characteristics being common to each vehicle.

Where dual guideways are necessary to carry a heavy traffic load, andspace is critical, the arrangement shown in FIG. 20 may be used. Thestructure includes a lower guideway 168 and a coextensive upper guideway170, which is spaced directly above the lower guideway on posts 172. Aroof 174 is supported above the upper guideway on posts 176. Thearrangement is adaptable to any of the vehicle types described andprovides for double the traffic flow within the ground space of a singleguideway.

For maximum ride comfort it may be desirable to control the dynamicmotion of the vehicle by some type of shock absorbing means,particularly at low speeds when the vehicle is riding on its wheels. InFIGS. 21 and 22, a typical airfoil supporting leg 178 has a telescopiclower portion 180 to which an airfoil 46 is attached. Cushioning isprovided by shock absorbers 182, secured between suitable structuralmembers 184 in upper leg 178 and a structural member 186 in the lowerportion 180. The shock absorbers may be spring or other resilient types,or fluid types which would allow ride adjustment. The wheel mounting,similar to that shown in FIGS. 7 and 9 and correspondingly numbered, isadaptable to the telescopic leg by attaching the upper end of theactuator 68 to a racket 188 on the structural member 186.

In a typical operation, starting from a flat surfaces terminal, thevehicle is moved on its wheels to the guideway, where the wheels arealmost entirely retracted to lower the airfoils to the guideway surface.With the main propulsion unit in operation, the vehicle is accelerateduntil the airfoils develop sufficient aerodynamic lift to raise thewheels from the surface, when retraction can be completed. if the wheelsproject sufficiently in the fully retracted position, the intermediateposition of retraction may not be necessary. As speed increases thevehicle will rise to its normal operating height in stable cruisingconfiguration. it should be noted that the vehicle will seek a stablelevel under a wide range of loading conditions. When heavily loaded thevehicle will ride lower, but the aerodynamic lift increases as theairfoil to surface gap decreases, so the action is self-balancing.

If the vehicle is subjected to a rolling condition, by wind or anyoflrer disturbance, indicated by the roll direction arrow 122 in FIG.10, the rudders 56 are deflected in the opposite direction to counterthe roll aerodynamically. The legs themselves provide a degree of rolldamping. In a simple rolling condition, or in stable flight, the lift isequal along the full span of each airfoil as indicated by the equallength directional arrows 124.

The arcuate form of the guideway 14 is ideal for making turns at highspeed. Since the center of mass 126 of the vehicle is well below thecenter of radius 128 of the guideway, the vehicle will tend to climb theextended outer wall 130 of a turn structure with a banking action. Inthe ideal condition, shown in FIG. 12, the acceleration load will bedownwardly in the direction of a line 132 through the center of radius128 and the center of mass 126, with no lateral accelerations affectingthe passengers. The lift is constant along the airfoil, as indicated byarrows 134, and is effectively directed toward the center of radius.

In the event that the vehicle is subjected to a lateral load, as byexcessive speed in a turn, the outboard portion of the airfoil, asrelated to the direction of turn, will be forced closer to the guidewaysurface. However, as shown in FIG. 11, the resultant lift will be higherat the outboard portion of the airfoil, indicated by graduateddirectional arrows 136 to 138, due to the non-constant airfoil tosurface separation. As a result, the vehicle will be aerodynamicallyreturned to the stable turn condition of FIG. 12, with aself-stabilizing action.

The automatic banking and stabilizing action, without the need forspecial guidance structure, ensures a smooth ride and greatly simplifiesguideway construction.

When approaching a destination, the vehicle is decelerated until theload is transferred to the wheels. The wheel hub motors 76 could bereadily adapted to spin up the wheels prior to contact with theguideway, to reduce tire wear. lfthe vehicle is to leave the guidewayfor lading and unloading, the wheels are extending to raise the airfoilsto clearance height.

It will be evident that the use of aerodynamic support in ground effect,makes it possible to use a simple light weight vehicle, requiringconsiderably less accessory and support equipment than a comparable aircushion type vehicle.

Having described our invention, we now claim:

1. In a mass transportation system,

an elongated guideway having a concave trough of arcuate cross section,

a vehicle, comprising an elongated body, with a plurality oflongitudinally spaced, vehicle supporting, aerodynamic lifting airfoilsmounted below the body substantially clear of aerodynamic interferencetherewith, said airfoils extending transversely to the length of thebody and having arcuate dihedral conforming to the cross section of saidguideway, to operate in ground effect with the guideway surface,

the radius of curvature of said guideway cross section being such thatthe effective center of mass of the vehicle is below the center ofradius, when the vehicle is riding in the guideway,

and propulsion means mounted on said vehicle.

2. A mass transponation system according to claim 1, wherein said bodyhas a pair of legs fixed to and supporting each of said airfoils, saidlegs being of streamlined cross section, at least some of said legs eachhaving a rearwardly extended lower portion, with a rudder pivotallymounted thereon, and control means connected to said rudders forselective operation thereof.

3. A mass transportation system according to claim 2, wherein at leastsome of said legs each has a rearwardly extended lower portion, with arudder pivotally mounted thereon, and control means connected to saidrudders for selective operation thereof.

4. A mass transportation system according to claim 2, wherein saidcontrol means includes roll sensing means in said vehicle, and actuatingmeans controlled by said roll sensing means to move said rudders in adirection to oppose the sensed roll.

5. A mass transportation system according to claim 4, wherein saidcontrol means further includes means for moving the rudders on each pairof legs in opposite directions.

6. A mass transportation system according to claim 2, and includingwheels retractably mounted in at least some of said pairs of legs, saidwheels extending below said airfoils.

7. A mass transportation system according to claim 6, and includingactuating means for extending said wheels sufficiently to raise saidairfoils clear of a flat supporting surface.

8. A mass transportation system according to claim 6, wherein saidairfoils have downwardly projecting tip plates thereon, said wheelsbeing movable between a retracted position projecting below saidairfoils slightly further than said tip plates, and an extended positionin which the airfoils are sup ported clear of a flat surface.

9. A mas transportation system according to claim 1, wherein certain ofsaid airfoils each has a flap pivotally mounted on a trailing edgeportion thereof to swing downwardly through a limited range, and controlmeans, sensitive to changes in pressure below the respective airfoil,connected to each flap.

10. A mass transportation system according to claim 9, wherein saidcontrol means comprises a cavity in the underside of the airfoil, apressure sensitive diaphragm mounted in said cavity and linkage meansconnected from said diaphragm to the associated flap to lower the flapwhen pressure below the airfoil increases.

11. A mass transportation system according to claim 1, wherein saidairfoils are spaced substantially equally along the length of said body.

12. A mass transportation system according to claim 1, wherein saidairfoils include a forward airfoil below the extreme front portion ofsaid body, and an aft airfoil below the extreme rear portion of thebody.

13. A mass transportation system according to claim 12, wherein saidbody has an underside portion of substantially arcuate convex crosssection conforming to said guideway, said airfoils being positioned tohold the body at a positive angle of incidence relative to the guidewaysurface and in ground effect proximity thereto.

14. A mass transportation system according to claim I, wherein saidguideway has slipstream deflecting baffles extending outwardly fromopposite sides and coextensive therewith.

InInAA nun

1. In a mass transportation system, an elongated guideway having aconcave trough of arcuate cross section, a vehicle, comprising anelongated body, with a plurality of longitudinally spaced, vehiclesupporting, aerodynamic lifting airfoils mounted below the bodysubstantially clear of aerodynamic interference therewith, said airfoilsextending transversely to the length of the body and having arcuatedihedral conforming to the cross section of said guideway, to operate inground effect with the guideway surface, the radius of curvature of saidguideway cross section being such that the effective center of mass ofthe vehicle is below the center of radius, when the vehicle is riding inthe guideway, and propulsion means mounted on said vehicle.
 2. A masstransportation system according to claim 1, wherein said body has a pairof legs fixed to and supporting each of said airfoils, said legs beingof streamlined cross section, at least some of said legs each having arearwardly extended lower portion, with a rudder pivotally mountedthereon, and control means connected to said rudders for selectiveoperation thereof.
 3. A mass transportation system according to claim 2,wherein at least some of said legs each has a rearwardly extended lowerportion, with a rudder pivotally mounted thereon, and control meansconnected to said rudders for selective operation thereof.
 4. A masstransportation system according to claim 2, wherein said control meansincludes roll sensing means in said vehicle, and actuating meanscontrolled by said roll sensing means to move said rudders in adirection to oppose the sensed roll.
 5. A mass transportation systemaccording to claim 4, wherein said control means further includes meansfor moving the rudders on each pair of legs in opposite directions.
 6. Amass transportation system according to claim 2, and including wheelsretractably mounted in at least some of said pairs of legs, said wheelsextending below said airfoils.
 7. A mass transportation system accordingto claim 6, and including actuating means for extending said wheelssufficiently to raise said airfoils clear of a flat supporting surface.8. A mass transporTation system according to claim 6, wherein saidairfoils have downwardly projecting tip plates thereon, said wheelsbeing movable between a retracted position projecting below saidairfoils slightly further than said tip plates, and an extended positionin which the airfoils are supported clear of a flat surface.
 9. A masstransportation system according to claim 1, wherein certain of saidairfoils each has a flap pivotally mounted on a trailing edge portionthereof to swing downwardly through a limited range, and control means,sensitive to changes in pressure below the respective airfoil, connectedto each flap.
 10. A mass transportation system according to claim 9,wherein said control means comprises a cavity in the underside of theairfoil, a pressure sensitive diaphragm mounted in said cavity andlinkage means connected from said diaphragm to the associated flap tolower the flap when pressure below the airfoil increases.
 11. A masstransportation system according to claim 1, wherein said airfoils arespaced substantially equally along the length of said body.
 12. A masstransportation system according to claim 1, wherein said airfoilsinclude a forward airfoil below the extreme front portion of said body,and an aft airfoil below the extreme rear portion of the body.
 13. Amass transportation system according to claim 12, wherein said body hasan underside portion of substantially arcuate convex cross sectionconforming to said guideway, said airfoils being positioned to hold thebody at a positive angle of incidence relative to the guideway surfaceand in ground effect proximity thereto.
 14. A mass transportation systemaccording to claim 1, wherein said guideway has slipstream deflectingbaffles extending outwardly from opposite sides and coextensivetherewith.